1. Field of the Invention
The present invention relates to a shackle structure for suspension leaf springs.
2. Description of the Related Art
Examples of shackles for suspension leaf springs, employed in the related art, are classified into structures such as, for instance, those described below.
That is, a structure may include pairs of left and right shackle plates, vehicle-body-side bushing support shafts (also hereinafter called “vehicle-body-side bush support shafts”) through each of which the upper portions of the shackle plates are connected to each other, leaf-spring-side bushing support shafts (also hereinafter called “leaf-spring-side bush support shafts”) through each of which the lower portions of the shackle plates are connected to each other, vehicle-body-side bushings (also hereinafter called “bushes”) fitted to the vehicle-body-side bush support shafts, respectively, and leaf-spring-side bushes (or bushings) fitted to the leaf-spring-side bush support shafts, respectively. A structure has heretofore been known in which the vehicle-body-side bush (or bushing) and the leaf-spring-side bush (or bushing) are split left and right in two halves, respectively (see, for instance, Utility Model Laid-Open No. 59-063005).
With such a related art structure, the vehicle-body-side bush and the leaf-spring-side bush are placed under a bilaterally symmetric state such that rigidity center positions of the vehicle-body-side bush and the leaf-spring-side bush are aligned in a vehicle widthwise direction.
With the shackles of the related art, however, the vehicle-body-side bushes and the leaf-spring-side bushes have rigidity center positions defined in the bilaterally symmetric state to be aligned in the vehicle widthwise direction. Therefore, during a turning motion of a vehicle, no change occurs in a toe angle of the wheels. This results in a difficulty of increasing driveability of the vehicle with an under-steer characteristic during a turning and traveling motion of the vehicle.